Akuma de sourou

High school is difficult for most kids. But for Kayano, a shy girl whose single mother seems to work all the time, it's even worse than usual. She's so afraid of drawing attention to herself that she can't tell the handsome Kamijo how much she loves him-until one day she finally gets up the courage to write him a letter confessing her feelings.
But her plans go awry when the letter falls into the hands of the school's most notorious student, Edogawa Takeru. To Kayano, Takeru seems to be Satan himself. Not only is he devilishly handsome, he is the son of the school's principal. To make things worse, her mother comes home to announce she's getting married to principal Edogawa!
But, in an unexpected twist, Kayano and Takeru gradually begin to grow feelings for each other the more they interact, but many obstacles gets in their way, but the biggest one of all was to face their parents who are soon to be married and come clean about their true feelings for each other.
                     -Wikipedia